Screw propeller



H. LEITNER.

SCREW PROPELLER.

APPLICATION FILED NOV. 4, 1 9-20.

H. LEITNER.

SCREW PROPELLEH.

APPLICATION FILED NOV.4, 1920.

1,414,742. ented May 2, 1922.

5 SHEETS-SHEET 2.

H. LEITNER.

SCREW PROPELLER.

APPLICATION FILED NOV. 4, 1920.

Patnted. May 2, 1922.

ETS-SHEET 3- 5 SHE H. LEITNER.

SCREW PROPELLER.

APPLICATION FILED NOV. 4, 1920.

l,4:l%,742@ I F Patented May 2,1922.

5 SHEETS-SHEET 4.

I 5 i c I l i l Z M 5 4 E fire/iron Z M W H. LEITNER.

SCREW PROPELLER.

APPLRCATION FILED NOV. 4, I920.

Patented May 2, 1922.

5 SHEETS-SHEET 5 Jhrnfbr can-m STATES,

PATENT o Flca.

nanny LEITNER, or LONDON, ENGLAND.

scnnw raorELLEn.

Specification of Letters Patent.

Application filed November 4, 1920. Serial No. 421,753.

formed as independent units, each of which is attached to the hub, andv the invention comprises improvements in the construction of the blades whereb the centrifugal stresses to which the blades are subjected are transmitted by the laminations directly to the hub, improved means for effecting the adjustability of the pitch of the-propeller and also improved means for attaching the blades'to the hub. v

According to the invention the blades are constructed with one or more of the lamina integral with the stems thereof.

In one arrangement for carrying the invention into practice each blade is advanta geousl constructed as described in the spe-. cificatlon of my Patent No.151693, that is to say, is composed of lamina orlaminae which .15, or are, extended with or without a joint round thebase portion of a pair of triangular driving plates which form the root of the blade, and which have extensions forming inner laminae for the blade. The stem or stalk of the blade is formed integral with the said plates and extension laminae. The said stem or stalk may be adjustably'secured within the socket provided on the hub to receive it, say, by means of a transverse bolt which extends'through the'socket and the stem or stalk ,the holes in thesocket or stalk being elongated so that a certain angular movement is permitted to the said bolt, wherebythe said stem or stalk can be turned within the socket. To clamp the said stem. or stalk in the positionto which it may be adjusted I may make use of a series of serrations or teeth upon the outer surface of the hub socket which engage with serrations or I teeth upon a bearing plate or washer through which the bolt asses. As will be-understood, by loosening the nut which tightens the bolt the serrations on the plate or washer may be freed from those on the hub socket, and the bolt, together with the stem or stalk, turned to the desired extent, after which the tightening of the nut will clamp the parts 1n the new position. p

In some cases the clamping plate previously referred to may be furnished with teethor serrations designed to engage'with teeth or serrations upon the hub, the adjustment and locking of the blade stem or stalk Patented May2,1922.

being effected through the medium of these mutuall engaging teeth.

The ub which may havet-wo, three'or 'more sockets may be made in one piece or it may be made in halves, preferably as stampings, pressings, or forgings which are adapt ed to be secured together in any convenient manner, as, for example, by bolts. Each of the hub halves is formed with a number, corresponding to the number of blades with which it is to be fitted, of semi-cylindrical depressions, the depressions on one half of the hub, when the two halves are broughttogether, being in register with those of the other half, so as to provide aseries of cylindrical sockets. In the case of the hub made in halves the stems or stalks 'may be held in position. radially through. the medium of a-niiular or bulbous extensions upon the 1nnerends of the saidfstems or stalks which are clamped between .the said halves of the hub in such a manner as topermit of the necessary turning movement for the adjust;

ment of the pitch of the propeller.

In some. cases, by

the hub sockets may be made to enter these --for fixation, the locking and *E ldJllSlZlllg! being similar to those above referred to.

In another arrangement where the blade.

In another arrangement all the laminations of each blade are continued to form the tubular stem or stalk. In the course of building up the blade, the tubular stem or stalk is built around and preferably attached to a sleeve or shell which formshan internal support giving rigidity to the said stem, and

over the stem so formed there may be passed providing a suitable in nor end to the propeller blades or laminae,

a second sleeve or shell which is secured to it by suitable means; The laminated blade stem is thus securely held between the two cylindrical shells or sleeves and is sufiiciently 'rigid to-withstand the stresses-towhich it is subjected in use. p a To efiable the invention to be fully understood, I will describe it by reference to the accompanying drawings. in wl1icl1 Figure 1 1s ail-elevation. with a part broken away. of the hub of a four-bladed propeller with variable pitch blades according to the invention and showing a portion of one only! of the said blades in position.

Figure 2 is a sectional elevation at right angles. to Figure 1. I

Figures Said 1 are views at right angles of a portion of one of thepropeller blades detached and,

' on the lines '11- 11 and 12--12, Figure 10.

F igure 5 is an underside view thereof.

Figure (S is a plan of a. blank which serves to form apart of the root of the blade.

F igure 7 is an elevation of half of a propeller .hub similar to that shown in Figure 1 but showing modified means for securing the blades to the hub after adjustment therein. v

Figure 8 is a sectional elevation at right an les to Figure 7, and

igure 9 is a section on the line 9-9, Figure 7. I I

Figure 10 is an elevation of a portion of one of the hub sockets for receiving the stem of a, propeller blade showing another arrangement for securing the said blade after adjustment;

.Figuresll and 12 are sections, respectively,

Figure 13 is 'a section illustrating the arrangement in which a blade stem fits outside a hub socket instead of within it.

Figure 14 is tin-elevation. of the root and stem of a blade showing the inner lining of the root made integral with the said stem.

Figure 15 is a section-on the line 15-15, Figure 11, and v Figure 16 is a plan of the said inner lining and stem.

Figure 17 is a perspective: view illustrating an integral construction of the inner I liningof the root and stem of a blade but i shown.

formed in halves in the directionof the length of the blades, one half only being Figure 18 shows an integral inner lining and stem as in Fi ure 17, but with the laminations forming 516 remainder of the-blade extended and fitting round the said stem.

Figure 19 is an elevation with a part removed of the hub of atwo bladed propeller with aportion -of the blade in position,

illustratinga modification in theconstruction of the blade stemand in the means for varying the pitch of the blade.

igure 20-is an end view and with reference to Figures 19 to 22. one of a the blades being shown in position and Figure 26 is a similar view to Fi ure 23 of the hub of a four-bladed propelle rf" 21: indicates the propeller blades, 1) the hub I v carrying the said blades and I) the propeller" shaft. e

In the arrangement illustrated in Figures 1 to 6, the blades (1 are advantageously constructed as described in the specification of my Patent No. 151693 as shown clearly in Flgures 3, 1 and 5, that is to say, each blade is composed of metal laminae 0. extended with or without a joint around the base portion (1? of, or extending between. a pair of triangular plates eat the root of the blade. The blank from which the base-piece and triangular plates are formed is shown "in Figure 6, two rectangular extensions or laminae f being also formed on the base piece (I to which the laminae c are attached. for instance; by screws f These triangular and rectangular extensions are bent along the dot and dash lines 9, Figure 6. into the position indicated in Figures 3 and 1, the

the edges of the said lamina! c themselves where they butt togetherafter leaving the said plates e.

h is the stem or stalk blade, which stem is cylindrical and formed integral with the base (1. and consequently with the laminae f, the .laminze 0 being secured to the said base-piece (l by a. clamping plate b ancf screws h. \YI

The hub is, as shown in'Figures 1 and 2, formed in halves, each half being, as above described, a metal stamping provided with semi-cylindrical depressions z. I when the halves are secured together. in a plane i at right angles to the axis of the pro eller shaft 1), by means-(of the bolts 17-, to 'orm the blade sockets .into which the stalks or, stems h are fitted. To prevent radial-movement ofthe said stems in the of each propeller deslgned,

sockets,. the former are provided with bulbous or annular ends [L3 designed to engage corresponding recesses V1' in the sockets.

The hub issecured to the propeller-shaft by keys or serrations and by frictional en- I serrations or teeth h.

5 at one end and the nut b at the other end. The taper end of the shaft 6 enters the taper sleeve 6 and is tightened therein frictionally by means of the nut b which enga es its projecting screw-threaded end I) an is fitted in the recessed end I) of the sleeve 5 keyways also being formed in the sleeve and shaft to receive keys b To secure the blades a ainst turning movement within the sockets 2', except when adjusting for pitch, I form each of the clamping plates h with one edge curved to a circle concentric with the centre of the connected stem and this edge I provide with These serrations. h on each blade engage with a corresponding set of serrations 2' on an extension or lug'on the socket carrying the blade, so that the blade is locked against any turning movement within the socket when the two parts of the hub are secured together. When, however, it'is required to alter the pitch of the blades, the two parts of the hub must be separated sufficiently to allow of lifting the blades to release them from the serrations i and turning them to the required extent when they are again moved into engagement with the said serrations and the parts of the hub again secured together.

I Figures 7, 8 and 9 illustrate an arrange ment wherein the bulbous or flanged end of the stem h is dispensed with and radial movement of the said stem is prevented by a transverse .bolt passing through the stem and hub socket- To allow of adjusting the pitch of the blades the holes j in the sockets 11 through which the said bolts pass are slightly elongated, asindicated in Figures 7 and 9, to allow the said bolts to turn with the stems h, and to permit of clamping the bolts, after such adjustment, serrations 3' are formed on the sockets i with which engage corresponding serrations on bearing plates or washers 7' when nuts j on the said bolts are tightened up. In the arrangement just described, the serrations are at an angle to the'axis of each socket i but in the arrangement shown in Figures 10 to 12 the serrations are parallel to the said axis. It

will of course be seen that in the last described arrangements, the stems h of the blades can be introduced into the sockets 1T radially, in which case the hub need not be made in halves connectedtogether as previously described. j

Instead of stems in the blades fitting within sockets on the hub as above described I may, as shown. in Figure 13, form stems'k on the hub b fitting within tubular blade stalks Z, transverse bolts m, similar to the bolts 3', being provided for securing and locking the parts together. It will of'course be understood that adjustment for pitch can in this arrangement also be provided for by 4 the like.

the use of serrations on the socket in conjunction with a serrated washer, as in the arrangements illustrated in Figures 7 to 12.

Figures 11 to 16 illustrate the construction wherein the stem or stalk of a blade having one or more laminae in addition to the outer sheath constituting the blade proper, is made integral with the inner lamina. a indicates the stem or stalk and 0 the inner lamina with which itis integral, a plate p being employed to clamp and secure by screws p the portions of the outer laminae g which are turned underneath the base piece 0 of said inner lamina.

Figure '17 illustrates a.co-nstruction of integral stem n and inner lamina 0 similar to that shown in Figures let to 16 except that the said integral stem and lamina are formed in halves, one half only being illus trated. The said halves. correspond with and fit within the outer laminae of the blade which is also formed in halves, the edges of which and also the edges of the lamina o and stem n being connected by welding or the like. In this arrangement the said outer laminae are also attached to the said inner lamina o similarly to the arrangement shownin the said Figures 14 to 16 in addition to the welding together, but in Figure '18 is shewn a construct-ion wherein the outer laminae are extended down and fitted around the stem, the whole being welded together along their common butt joint.

In the arrangement illustrated in Figures 19 to 23 in which the laminae c gradually change from the aerofoil section to that of the cylindrical stem, r is the inner sleeve or. shell around which the said laminae are built to form the stem, the buttin edges of which laminae are connected toget er and also to the said sleeve at 0 by welding or s is the second sleeve or shell the whole being conpassed over the stem.

This shell 8 nected together by rivets s is bulbous or flanged as at t to prevent radial movement of the blade in one direction in the hub socket and has integral therewith or connected thereto by welding or the like a disc at between which and another disc u which forms a closed end to the sleeve 1 are arranged the turned-in ends of the laminae, the whole being clamped together by the screwed plug 2;. Instead of the disc u being separated from thesleeve r it may be integral therewith as shown in Figure 24. In some cases the sleeve 8. may be dispensed with, the edge of the disc 25 serving to prevent radial movement of the blade in one direction. The radial movement of the propeller blade in the other direction is prevented by a sleeve 0 Figures 19, 21 and 23, "for the propeller shaft, and which sleeve is formed integral with one half of the hub and secured to the other half by .a nut Or the sleeve may be separate from the hub and secured thereto in any suitable wav.

tween the blade stems and the said sleeve. $0 the said distance pieces screwing into holes a in the plugs '12.

For adjusting the blades in the hub sockets in order to alter the pitch thereof, bolts clamping plate.

3. screwpropeller asclaimed in claimw are pivoted to lugs w on the blades and pass through holes in lugs w on the hub sockets and are secured thereto by nuts 3 as clearly shown in Figures 19 and 20. The blades are also held against turning movement in the hub sockets by friction therewith. To enable adjustment of the blades to be effected, the bolts 2' and the nuts 12 must be slackened to unclamp the sockets from the stems when the latter can be turned.

As will be understood, the sides of the stem or stalks may be parallel as already shown, or they may be tapered in either direction. Furthermore, it will be understood that, although I prefer to use the laminated stem or stalk as above described, yet I may, in lieu thereof, use a stem formed from taper gauge metal, such a stem being em- .ployed either with or without the shells or sleeves above described.

Propellers constructed in accordance with the invention are suitable for use with aircraft of any type, including the ordinary heavier than air machines, helicopter machines, or machines of the lighter than air type.

Claims:

1. A screw propeller comprising blades built up of metal laminae and provided with stems, a hub provided with sockets to receive said stems, means' for adjusting said stemsin said sockets for varying the pitch, said blade stems being made integral with one or more of said laminae.

2. A screw propeller as claimed in claim 1, the stem of each blade being integral with the innermost lamina of said blade, said lamina comprising a base piece adapted to carry the stem and triangular and rectangular extensions for the attachment of the remaining laminae, which are carried beneath said base piece, said remaining laminae being secured to said base piece by means of a 1, wherein the integral inner lamina and stem are made in halves, substantially as described.

4. A screw propeller as claimed in claim 1, in -which' each blade is provided with teeth adapted to engage corresponding teethin connection with the hub for securing the '1, wherein the blade stems blade in any desired position after adjustment for pitch.

5. A screw propeller as claimed in claim 1, the stem of each blade being integral with the innermost lamina of said blade, said lamina comprising a base piece adapted to carry the stem and triangular and rectangular extensions for the attachment of the remaining laminae, which are carried beneath said base piece, said remaining laminae being secured to said base piece by means of a clamping plate, said clamping plate being provided with teeth which engage similar teeth formed on the hub to secure the blade in any required position.

6. A screw propeller as claimed in claim are provided with transverse bolts, said bolts being adapted to be passed through the stems and the hub sockets. to prevent the radial movement of the blades.

7 A screw propeller as claimed in claim 1, wherein the blade stems are provided withtran-sverse bolts adapted to be passed through the stems and the hub sockets, to

prevent radial movement of the blades, said bolts being provided with toothed washers, adapted to engage similar teeth in the hub sockets for securing the blades after adjustment.

8. A hub for a screw propeller, composed of two parts each having semi-cylindrical depressions which form sockets for the blade stems of said propeller when the two parts are clamped together, said clamping holding the blades in position in the hub frictionally, a propeller shaft being connected to said hub by a sleeve, formed integral with one part of the'hub.

9. A screw-propeller as claimed in claim 1, wherein the inner ends of the stems of the blades are formed or provided with annular or bulbous extensions to prevent radial movement of the said blades relatively to. the hub, substantiallyas described.

10. In a screw-propeller as claimed in claim 1, the combination with that portion ofthe laminae of each blade which forms the stem, of an inner sleeve or shell secured to the laminae, substantially as described.

11. A screw propeller comprising blades built up of laminae, the stems of said blades being provided with an inner sleeve and an outer sleeve, said outer sleeve having an annular extension. said two sleeves being secured to the-laminae.

12. A screw propeller, comprising blades built up of laminae, the stems of said blades 

